Skylines are becoming less visually attractive due to the addition of tall structures that are not visually integrated into their surroundings and therefore stand out against their backgrounds, which frequently includes the sky. For example, with the continuing proliferation of mobile communications devices such as cellular telephones, personal digital assistants (PDAs), pagers, text messaging devices and the like, mobile communications service providers are constructing more and more antenna facilities, including cell towers, to improve the quality of existing services, increase the variety of services offered and increase the coverage area of their services. Thus, service providers are not only adding more cell towers to urban and suburban regions where cell towers already exist, they are constructing new towers in regions where no facilities had existed. In addition, a service region may have more than one service providers, each having its own cell towers separate from the cell tower(s) of the other service provider(s).
To optimize a cell tower's coverage area, the cell tower should generally have its antenna(s) located high above the ground and at a location unobstructed by adjacent objects, such as buildings, trees and mountains, among others. To achieve this goal, cell towers typically extend above the highest features within their respective coverage area. Since cell towers generally extend above most or all of surrounding objects, viewers typically view these structures against a background sky.
Until relatively recently, service providers made no attempts to lessen the visual impact of their cell towers, other than perhaps painting them a with a light-color paint, such as a neutral gray. However, due to the large number of cell towers being constructed and increased concern over the aesthetic impact of these cell towers, more and more communities are banning cell towers within their jurisdictions. In response, service providers are attempting to make their cell towers more attractive, e.g., by disguising, or camouflaging, them as other objects, such as trees and cactuses. The realism of such disguises, however, has generally been less than desirable because the cell towers are typically significantly larger than typical simulated object and the geometrical requirements of the cell towers are not suited to simulating such objects.
Other conventional visual camouflaging techniques are generally not suitable for reducing the visual impact of cell site antennas and support towers. Conventional visual camouflaging techniques are generally one of two types. The first type is used when the environment surrounding an object to be visually concealed is non-uniform, i.e., contains a plurality of juxtaposed regions that visually contrast with one another to form repeating patterns, random patterns or a combination of repeating and random patterns. Such patterns are found in, e.g., cityscapes, landscapes and seascapes, which are generally viewed horizontally, and aerial views of natural and manmade features on the surface of the earth. In this type of camouflage, the goal is provide a pattern, or image, that simulates a pattern contained in the background against which a structure is viewed between a viewer and the structure so that the viewer confuses the simulated pattern with the background pattern and thus cannot readily distinguish the outline and/or other features of the structure from the background.
Examples of pattern camouflaging include U.S. Pat. No. 1,305,296 to MacKay and U.S. Pat. No. 2,292,848 to Robson. Each of these patents discloses a technique of painting a ship with various patterns comprising discrete regions of certain colors. In MacKay, the pattern is designed to simulate a seascape. In Robson, the pattern provides a compromise between concealment against a seascape and deceiving an observer as to attributes, such as size, shape, speed and direction of travel, of the ship once the ship has been spotted. Creating patterns from discrete regions of different colors is not suitable for concealing a structure against a generally uniform background such as the sky.
Examples of image camouflaging include U.S. Pat. No. 5,142,833 to Svehaug, U.S. Pat. No. 5,373,863 to Prizio and U.S. Pat. No. 5,220,631 to Grippin. Svehaug discloses a camouflage screen comprising a panel for placing between a user and an observer. The panel has a planar reflective surface that, when properly positioned, generally faces and is slanted toward the observer so that the user is concealed behind the panel and an image of the terrain below the slanted panel is reflected to the observer. Prizio discloses a camouflage blind for placing between one or more users and an observer. The blind comprises a plurality of panels pivotably attached to one another along adjacent edges so that the blind can be easily stored, transported and set up in the field. Each of the panels includes a planar reflective surface that, when properly positioned, generally faces the observer and reflects to the observer an image of one or more objects contained in the foreground of the reflective surface. The devices of Svehaug and Prizio are not suitable for being mounted on a structure, such as a cell tower.
Grippin discloses a camouflage device that uses optic fiber cables to conceal an object by transferring an image of the background (as viewed by a viewer) of the object to the foreground of the object. The device comprises a plurality of background imaging lenses, a plurality of foreground imaging lenses and a plurality of optic fibers that each connect a background imaging lens to a corresponding foreground imaging lens. The background imaging lens creates an image of the background that is transferred to the foreground imaging lens via the corresponding optic fiber. The foreground lens then forms an image of the background that is viewed by the viewer in the foreground of the device. Due to the necessity for optical quality lenses and the complexity of this device, it is not a practical option for camouflaging a large structure, such as a cell site antenna support tower. In addition, this device would be difficult, if not impossible, to adapt to provide such images for a full 360° around a structure.
The second type of camouflaging technique is used to conceal an object against a background having a generally uniform composition of hue, saturation and brightness, wherein the object subtends a small arc of view. An example of this technique is U.S. Pat. No. 4,611,524 to Ferris, which discloses a camouflaged vehicle, such as an aircraft, surface vehicle or the like, at least a portion of which remains undetected until the vehicle subtends an arc of substantially five minutes when used against at least one predetermined light background reflectivity. One surface of the vehicle includes a substantial area of a predetermined reflectance that matches the reflectance of the predetermined light background. The area includes at least three defined portions, at least two of the portions having different reflectance so that when the reflectance of one of the defined portions is added to the total reflectance of the others of the three defined portions and the results averaged, they will have a reflectance substantially that of the predetermined light background. A limitation of this technique is that it is only suitable for objects subtending small arcs of view. Thus, this technique is not effective for large objects, such as cell site support towers, that are frequently viewed at a subtended arc of much greater than five minutes. In addition, this technique is not suitable when the foreground is brighter than the background.
In view of the foregoing, there is a need for a camouflaging technique that is economical and is capable of providing a large structure, such as a cell tower, with reduced visibility against a background, such as the sky, having a generally uniform composition of hue, saturation and brightness.